Process of preparing cycloalkanes



Patented Apr. 14, 1'94? x V m l-r1 1 -sTA' 'Es-'-rhflieii WalterSchmidt,Frankfort-on-the-Main-Hochst, V

Franz Josei'Pohl, Hofheim in Taunus, and Otto Nicodemus, Frankfort o'nthe -'Main Hochst, Germany, assignors, by mesne assignments, to WinthropChemical Company, Inc., vNew York, N. Y., a corporation of New York NoDrawing. Application March 11, 1939, SeriaL .No.'261, 374.- In GermanyMarch 12, 1938 V v SClaims. ((71.260-666) I p w H V r The presentinvention relates to a process of carboxylic acids and nitriles thereof;for instance Preparing cycloalkanes. Iormamide, 'methylacetamide,.lauric acid-amide,

. It is known that dibromalkanes such as 71:3-dibenzenesulfonamide, para-toluenesulfonamide, bromopropane yield cyclopropanein the presenceisohexylic acid-nitrile, butyl butyrate, voxalic of zinc and aqueousalcohol. 'In industry this tnacid-diethyl ester,- ethyl-urethane or thelike.

. process-has many drawbacks.- On the onehand The expression solublecomplex compound means the separation of the twobromineatoms is not Ithatthecomplex compound is to be soluble in V uniform, asbesides thering closurethere may be v the excess of the organic complex-formingcomobserved the formation of considerable quantities pound used... heatte h ef mustbe-used of hydrogen and, in consequence thereof, of pro insuchaquantity that the zinchalide formed is pane. 0n thevother hand alarge excess-of zinc dissolved during the (reaction. Generally at leastI is necessary; especiallywhen the. zinc halide about3 to 5 mols oi thecomplex-iorming comformed has the opportunity of encrustingthe nound'should be used for-1 moi-of the.dihalo-. surface of the metal. 7 V rgenalkane. Depending on the .parent material a A modification of thismethod which consists .5 used the temperatu e ec sa y fo t reaction 1ngradually addin th dibromoppppgne t th mayvary between 'roomtemperatureand about reaction mixture instead of mixing the zinc dust, 150 C. Itmay besuit'able tostart the reaction the solvent and the dibromopropaneas usual and at raised temperature and to complete it at room causingthem to react simultaneously, also int mp ra re T a t n is s ed h n svolves no essential advantage, 7 V f O-no longer escapes from themixture. Depending li it be attempted to use dichloroalkanes upon the.parent material used it is possible to instead of dibromalkanes thereaction with choose from the great number of substances the zinc occursmuch more slowly. It,has,. which can be used the complex-forming com- 7therefore, been proposed to use as" solvents pound which afiords thebest working conditions ethers and hydrocarbons having a higherlboiling3 for thedesire'd reaction. r v V 7 point than dichloropropanemonies-(to permit 1 For amideh s rov d to e e ec l y useful use of ahigher reaction temperature: and to acinlm yir ifl si ibi as s a i flb'1 d in celerate'and improve the'reaction. .Inthis case, Q such anexcess that the zinc complex compound 7 however, the drawbacks describedabove are 'esf remains dissolved during thereactiong The most observed,as the metal i su 1 face;lis,then 39 suit blerat o is about5 to aboutlOmols oi r rm- I r particularly stronglyencrustedby the z'incich lo';amldetoxl moi of dihalogenalkane, The reacride formed. Y a tion.oifibromopropane withzinc-to form-cyclo- In order to avoid these drawback's'and to make arotene-may; f rin n eo e r ed out with it possible tooperateat a 1ow temperature it -f he e i in he r e e o am de even beenproposed to introduce alkali iodide'into the v t tw cte p atura-about C.to aboutr reaction, By'the presence of iodine ions'which 0., the finalproduct being practically pure so cause an intermediate formation ofiodoalkanes .that'further complicated and expensive P r it was hoped tofacilitate the reaction with the tlonprocesses are unnecessary. Incontrast with zinc. I 7 theknown processes in which a considerable ex- 7Now we have found that 'dibromalkan and ,cess ol' rzinc-e-up to 400per.cent-.-is used the presdichloralkanes may especiall -readily, be tan Tent process requires only about that quantity 7 formed into thecorresponding cyclic compound which is 'calculated'ior the reaction.Similar inby causing zinc to act'upon a compound o'ithe dustrialprogressfollows the use of other comgeneral formula 4 poundsfimentionied above;7

CHx H c 0. For e reac ion there may be used 1:3-di- .0 Inn-R .7 jchloropropane; 1:3-dibromopropane-; l-chlorowherein X1 and X: stand forchlorine or brop 3-bromopropane;- 1t3.-dichloro-n-butane; 1:3-

mine and R stands for hydrogen or methyl, in dibromo-pn-butane. When1:3-dihalogen-n-buthe presence of an organichcompound capable of tonesare used methyl cyclopropane is formed.

1011111118 Soluble complex mp nds with the zinc The following examplesserve to illustrate the h i formed- I Y V -invention, but they are notintended to limit it As compounds capable of forming soluble comthereto;the parts are by weight, parts by'volurne Dle! compounds with the Zincchloride or zinc having the same ratio to parts by weight that bremldetermed there may be used amides of carthe liter has to the kilo.

. I boxylic acids and sulfonic acids, esters or organic 5 (1) 2920 partsof pure lz3-dibromopropane,

' 'bron'io-n but'ane in 150 parts-by volume free from 1:2-dibromopropaneare introduced drop by drop, while stirring, into a suspension heated to40 C. of 722 parts of zinc dust con-V tamingeo per cent of active 'zincin 2250 parts",

After the reactiomhasset in the! of formamide.'

temperature'is reduced to about 14 C. to about and-is liquefied bycooling. After all the' di'e heated for a short time to; 40 C. until thereaction is ilnished' The yield amounts' to ahoveJQ OK per cent of thetheory;

(2) As described in Eifii ifi, a mimi 01 1s 1188 parts of1:3-dibromo-n-butalne and i 397- parts of zinc dust containing 90 percent'of active zinc is caused to react in'1238 parts of form.-

amide, but after the reaction has set in the ternperature isrkept atabout C. The"gas pro- 20, ;duced contains 99.6 to99.7perfcent'otrmethyl- I I cyclopropane; theyield amounts to above-90per center the theoryf 5 z f (3) A mixture of 5 parts of "1:3'-'dichloro'-nw butane, "parts of zinci-dusbcontaihing 90 per :25

' cent, of active zinc" and 150' parts by volume of N-methylacetainideis"ca utiously heatedyv'vhilef I stirring, until the evolut'ioniof gassets ing'iiir ther parts of lz'3-dichloro-n-butane are thenintroduced'drop byQdrop m suchf-a mannerthat 3V 'thetemperatureremainsnearly? constant. The Q liquefied product contains 98.2 per-'cent'ofmeth ylcyclopropane ,7 i 1 1' "(4) "68 parts of 1;3-dibromo'propane arecaused to react, as described in Example 3; with a mixture of parts of'zinc 'dust'cont aining' per cent-ot activ'e zinc ISO p'artsbyvoIunie ofbutyl' butvrate. The reaction product contains" *99j3' 'per cent of;cyc1opropme. ;me yield amounts-to 93 per center the theory.:- 4

(5) In a manner analogous tothatdescflbed in Example 1' 3; '68 parts or1 ;3-Eiibroniopropane' I are "caused to react=witha mixture of'50ipartsof zinc dust containing 90 percent 'otjactiv' zinc. 1 in partsby volume or p rid ne? Alli-DQ1105 is obtained ma ood yie1d'containiij1g99 per cent l iheif?" a a ;(6) Ida mariner analogous thatdescribed a cyclopropane. Theyield amounts to 92 per cent of the theory.(7) 788 parts of pane are; caused to react, jas described in Example 1,with. a mixture of 361 parts of zinc dust containing 90 per centof-active zinc in 1125 parts. oi! tormamide. The reaction productcontains I 99.6' per cent E1 of cyclopropane. The yield amounts to about;96 per cent of the theory. We

i 1. In the process offpreparing cyclopropane thestep'which'comprisescausing a mixture congeneral; ior nula' sistingof zinc-dust and1:3-dibromopropane to react inthepresence of about-5 mols of form?-amide calculated upon 1 mol'oi 1:3-dibromopropane." ff T i 2;Inthe'process of preparing methylcyclopro' pane the step whichcomprisescausing a mix ture consisting of'zinc dust and lza-dibromo-nbutanetoreact in'the presence orabo'ut 5 mols oi 1 I 3. ml the pr 'ess'f ofpreparing cyclopropane w the step whichcomprises' 'causing a' mixtureconsisting' oi zinc dust and lichloro-3- -bromopro I pane to 'reacvm',the'presence "ofabout 5 mols of tormamidecalciilated upon i1 incl oQI-chloro-B- bromopropane.

the'presence offoi'mamide.

5. In the process of preparing aliphatic cyclic. hydrocarbons Icontaining three cyclic 508111011 5 atoms the step whichcomprisescausing} mixfleqe a c m nd r mxi-cmz-fcflxi-fiz li s sen Iii lielq eniel e dl fi h eis i sc bl ot and b'mmfi a stands" I a subs'tituentselected "Irom ItheIgrouD snnsiori mr ienm wuo .J iew 1n mm. i li llqunt u rm niide I capableot dissolvlng thgcomplex Ionnamidetureconsisting'o W som 'F RANZ JOSEFPOHL. T T CQPW i halidecompound formed;

pure l chloro-3-bromoproe

